FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“CEILING FAN WITH AERODYNAMIC SLEEVE”
We, Bajaj Electricals Limited, an Indian National, of 45/47, Veer Nariman Road, Fort Mumbai- 400001, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention relates to the field of air circulation systems. In particular, the present invention provides a sleeved ceiling fan blade for noise reduction.
BACKGROUND OF THE INVENTION
Ceiling fans are ubiquitous in every household and commercial areas in tropical areas, particularly India, and are the primary and cost-effective mode of cooling an area. The rotating mechanism of ceiling fans circulates the air in an area by pushing air down, which forces the cool air near the floor to move outward and stir the air at the edges of the room. This movement of air can create a cooling effect.
Currently available ceiling fan blades are typically made of metal, which have side bend or the center curvature as profile along the section of the blade. These features are usually for increasing air circulation, however, they lead to increased noise levels. Aerodynamic profiles to reduce noise levels are currently not available in metal blades. Redesigning metal blades and fabrication can be expensive and time-consuming exercise. Therefore, there is a need devise new methodologies to reduce noise, while at the same time reducing costs.
SUMMARY OF THE PRESENT INVENTION
In an aspect of the present invention, there is provided a sleeve (100) for a ceiling fan blade (104) attached to the leading edge (102) of the fan blade (104) having an upper surface (106); a lower surface (108); and a transition region (110) at one end of the sleeve connecting the upper surface (106) to the lower surface (108).
In another aspect of the present invention, the upper surface (106) of the sleeve (100) is curvilinear; and the lower surface (108) is curvilinear or substantially flat.
In another aspect of the present invention, the radius of curvature of the curvilinear upper surface (106) or the curvilinear lower surface (108) of the sleeve (100) is in the range of 10-100 mm.
In yet another aspect of the present invention, the radius of curvature of the curvilinear upper surface (106) or the curvilinear lower surface (108) of the sleeve (100) is in the range of 50-80 mm.

In still another aspect of the present invention, the transition region (110) of the sleeve (100) has a rounded profile having diameter in the range of 1-25mm.
In another aspect of the present invention, the transition region (110) of the sleeve (100) has a non-rounded profile.
In an aspect of the present invention, chord length for the transition region of the sleeve (100) in the range of 1 - 10mm.
In another aspect of the present invention, the width of the sleeve (100) (w) is in the range of 2-200mm.
In still another aspect of the present invention, the width of the sleeve (100) (w) is in the range of 20-60mm.
In yet another aspect of the present invention, the length of the sleeve (100) (l) is in the range of 10-800mm.
In an aspect of the present invention, the length of the sleeve (100) (l) is in the range of 100-500mm.
In another aspect of the present invention, the sleeve (100) is fixedly or detachably attached to the leading edge (102) of the ceiling fan blade (104).
In an aspect of the present invention, there is provided a ceiling fan blade (200) comprising at least a sleeve (100), said sleeve (100) is attached to the leading edge (102) of the fan blade (104) having an upper surface (106); a lower surface (108); and a transition region (110) at one end of the sleeve connecting the upper surface (106) to the lower surface (108). The fan blade is be made of one material selected from the group of plastic, metal, polymer, and the like.
In an aspect of the present invention, there is provided a ceiling fan (300) comprising at least a ceiling fan blade (200), said ceiling fan blade (200) comprising at least a sleeve (100), said sleeve (100) is attached to the leading edge (102) of the fan blade (200) having an upper surface (106); a lower surface (108); and a transition region (110) at one end of the sleeve connecting the upper surface (106) to the lower surface (108).

This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
Fig. 1 depicts a first cross-sectional view of the sleeve for a ceiling fan blade, in accordance with an embodiment of the present invention.
Fig. 2 depicts a second cross-sectional view of the sleeve for a ceiling fan blade, in accordance with an embodiment of the present invention.
Fig. 3 depicts the top view of the sleeve for a ceiling fan blade, in accordance with an embodiment of the present invention.
Fig. 4a depicts the flow-analysis of ceiling fan blade with sleeve, in accordance with an embodiment of the present invention.
Fig. 4b depicts the flow-analysis of ceiling fan blade without sleeve, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Those skilled in the art will be aware that the invention described herein is subject to variations and modifications other than those specifically described. It is to be understood that the invention described herein includes all such variations and modifications. The invention also includes all such steps, features, and methods referred to or indicated in this specification, individually or collectively, and any and all combinations of any two or more of said steps or features.
For convenience, before further description of the present invention, certain terms employed in the specification, examples are collected here. These definitions should be read in light of the remainder of the disclosure and understood as by a person of skill in

the art. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art. The terms used throughout this specification are defined as follows, unless otherwise limited in specific instances.
As used in the specification and the claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.
The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only.
The present invention provides a sleeve for a ceiling fan blade attached to the leading edge of the fan blade having an upper surface; a lower surface; and a transition region at one end of the sleeve connecting the upper surface to the lower surface.
In an embodiment, the upper surface of the sleeve is curvilinear. In an embodiment, the lower surface of the sleeve is curvilinear. In an embodiment, the lower surface of the sleeve is substantially flat. In an embodiment, the upper surface and the lower surface of the sleeve are curvilinear. In a preferred embodiment, the upper surface of the sleeve is curvilinear and the lower surface is substantially flat. The radius of curvature of the curvilinear upper surface or the curvilinear lower surface of the sleeve is in the range of 10-100 mm. In an embodiment, where the upper surface and lower surface both, of the sleeve are curvilinear, the radius of curvature of the upper and lower surface are same. In another embodiment, where the upper surface and lower surface both, of the sleeve are curvilinear, the radius of curvature of the upper surface is more than that of the lower surface. In yet another embodiment, where the upper surface and lower surface both, of the sleeve are curvilinear, the radius of curvature of the upper surface is less than that of the lower surface. In a preferred embodiment, the radius of curvature of the curvilinear upper surface of the sleeve is in the range of 50-80 mm. In an embodiment, the radius of curvature of the curvilinear lower surface of the sleeve is in the range of 50-80 mm. It is understood by a person skilled in the art that the radius of curvature of the curvilinear upper surface and the curvilinear lower surface of the sleeve can be selected as per particular requirement of the fan blade or fan.

In an embodiment, the transition region of the sleeve has a curved profile. The diameter of the curved profile is in the range of 1-25mm. In a preferred embodiment, the diameter is in the range 1 – 10 mm. In a particular embodiment, the diameter of the curved profile is 4.2mm. In another embodiment, the transition region of the sleeve has a non-curved profile.
The sleeve of the present invention further comprises a leading edge and a trailing edge, wherein the chord length of the sleeve in the transition region is in the range of 1–10 mm. In a preferred embodiment, the chord length for the transition region is in the range of 2-7 mm. The width of the sleeve is in the range of 2-200mm. The width of the sleeve may vary based on fan blade width, maximum fan speed. The length of the sleeve is in the range of 10-800mm. The length of the sleeve may vary based on fan blade length, maximum fan speed.
In an embodiment, the sleeve is fixedly attached to the leading edge of the ceiling fan blade. In another embodiment, the sleeve is detachably attached to the leading edge of the ceiling fan blade. The sleeve may be attached to the leading edge of the ceiling fan by any means generally known to a person skilled in the art, including, but not limited to, snap fitting, welding, etc.
The present invention also provides a ceiling fan blade comprising at least a sleeve, said sleeve attached to the leading edge of the fan blade having an upper surface; a lower surface; and a transition region at one end of the sleeve connecting the upper surface to the lower surface. The fan blade is be made of one material selected from the group of plastic, metal, polymer, and the like.
The present invention also provides a ceiling fan comprising at least a ceiling fan blade comprising at least a sleeve, said sleeve attached to the leading edge of the fan blade having an upper surface; a lower surface; and a transition region at one end of the sleeve connecting the upper surface to the lower surface.
The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical

and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs.
As seen in Fig. 1, there is a provided a cross-sectional view a sleeve (100) attached the leading edge (102) of a ceiling fan blade (104). The sleeve (100) can be fixedly or detachably attached to the fan blade (104). The sleeve (100) can be made of any material such as plastic, rubber, polymer, and the like. The sleeve (100) has an identifiable upper surface (106), lower surface (108), and a transition region (110) connecting the upper surface (106) and the lower surface (108). In a preferred embodiment, the upper surface (106) has a curvilinear curvature having radius of 68 mm and the bottom surface (108) is substantially flat. The transition region (110) has a curved profile having a diameter of 4.2 mm. The thickness of the sleeve (100) is 1.1 mm. The upper surface (106) of the sleeve (100) has a trailing edge (112a), and the lower surface (108) of the sleeve (100) has a trailing edge (112b). As seen in Fig. 2, the height (h) of the sleeve (100) attached to a the ceiling fan blade (200) is 5 mm, while the width (w) of the sleeve (100) is 30 mm. As seen in Fig. 3, in a particular exemplary embodiment, the length of the sleeve (100) (l) extends to substantially cover the leading edge of the fan blade. It is to be understood that the dimensions of the sleeve (100) are not restricted to the particular values disclosed herein and can be readily varied as per requirements.
Fig. 4a-b shows the flow analysis of air turbulence at the leading edge of the blade. As seen in Fig. 4a, in blade with sleeve (100) attached to the leading edge of the blade, the air turbulence is significantly reduced as compared to turbulence at the leading edge of blade without sleeve (Fig. 4b). The sleeve reduces the inflow vortices and delays the flow separation at the same angle of attack of the blade, thus reducing the amount of noise generated by the blade. At full RPM, a minimum reduction of 3 -7 dB in noise was observed, while air delivery of the fan was unchanged in both conditions (with and without sleeve). Additionally, the sleeve (100) also serves to increase the stiffness of the blade, thus causing less vibrations/ flapping during operation. Ordinary metal blade fan as known in the art, at full RPM, gave a noise reading of 59-62dBA (as per IS 1391-2 standard). In contrast, the fan comprising the sleeve of the present invention gave a noise reading of 55-56dBA measured as per the IS 1391-2 standard. These clearly show the advantage of the present invention over the prior art.

Overall, the present invention provides a sleeve (100) for attaching with the leading edge of a fan blade, which provides lesser noise during operation, better air delivery (low turbulence), consistent air delivery, and durable blades.
Reference numerals:
Sleeve (100);
Ceiling fan blade (104, 200);
Leading edge of ceiling fan blade (102);
Upper surface of ceiling fan blade (106);
Lower surface of ceiling fan blade (108);
Transition region of sleeve of ceiling fan blade (110);
Width of sleeve of ceiling fan blade (w);
Length of sleeve of ceiling fan blade (l);
Height of sleeve of ceiling fan blade (h); and
Ceiling fan (300).

I/We claim:
1. A sleeve (100) for a ceiling fan blade (104) attached to the leading edge (102) of the fan blade (104) having an upper surface (106); a lower surface (108); and a transition region (110) at one end of the sleeve connecting the upper surface (106) to the lower surface (108).
2. The sleeve (100) as claimed in claim 1, wherein the upper surface (106) is curvilinear; and the lower surface (108) is curvilinear or substantially flat.
3. The sleeve (100) as claimed in claim 2, wherein the radius of curvature of the curvilinear upper surface (106) or the curvilinear lower surface (108) is in the range of 10-100 mm.
4. The sleeve (100) as claimed in claim 3, wherein the radius of curvature of the curvilinear upper surface (106) or the curvilinear lower surface (108) is in the range of 50-80 mm.
5. The sleeve (100) as claimed in claim 1, wherein the transition region (110) has a curved profile having diameter in the range of 1-25mm.
6. The sleeve (100) as claimed in claim 1, wherein the transition region (110) has a non-curved profile.
7. The sleeve (100) as claimed in claim 1 comprising a leading edge and a trailing edge, wherein the chord length for the transition region of the sleeve (100) in the range of 1 - 10mm.
8. The sleeve (100) as claimed in claim 1, wherein the width (w) of the sleeve (100) is in the range of 2-200mm.
9. The sleeve (100) as claimed in claim 8, wherein the width (w) of the sleeve (100) is in the range of 20-60mm.

10. The sleeve (100) as claimed in claim 1, wherein the length (l) of the sleeve (100) is in the range of 10-800mm.
11. The sleeve (100) as claimed in claim 10, wherein the length (l) of the sleeve (100) is in the range of 100-500mm.
12. The sleeve (100) as claimed in claim 1, wherein the sleeve (100) is fixedly or detachably attached to the leading edge (102) of the ceiling fan blade (104).
13. A ceiling fan blade (200) comprising at least a sleeve (100) as claimed in claim 1.
14. The ceiling fan blade (200) as claimed in claim 13, wherein the fan blade (200) is be made of one material selected from the group of plastic, metal, polymer, and the like.
15. A ceiling fan (300) comprising at least a ceiling fan blade (200) as claimed in claim 13 and 14.